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图像末制导仿真技术的研究
王莹
学位类型博士
导师王延杰
2014-07
学位授予单位中国科学院大学
学位专业机械电子工程
摘要图像末制导仿真系统可以作为外场武器的模拟跟踪、检测系统,还可以根据生成的特定仿真场景模拟对不易实验地区(例如城市)的作战试验。在虚拟仿真领域中,虚拟图像的实时生成速度以及虚拟场景的生成效果是衡量虚拟场景沉浸效果和程度的两个重要指标。对于数据量较小的虚拟仿真系统两个指标可以兼顾,但是对于大规模虚拟仿真系统场景的逼真度越高,系统的漫游速度可能越低,因此两个指标要权衡考虑。 本课题针对虚拟仿真场景的这两个重要指标展开研究,主要包括以下几个方面的内容。 在仿真系统中为了模拟真实感地形采用读取DEM高程数据渲染地形的方法,并对于不同飞行阶段的地形采用不同分辨率的真实图像作为地形纹理。为了避免相邻不同分辨率的纹理出现视觉跳跃的现象,采取了相应的图像融合策略生成过渡纹理的方法,逼真的模拟了导弹渐近的过程。对于卫星盲区地形,采用了基于ROAM算法的自适应地形算法生成的虚拟地形。将基本ROAM算法生成的地形作为基网格,计算下一级网格顶点的粗糙度以及与视点的距离等综合参数。通过给定阈值与综合参数的比较来判断是否继续细分。对于满足细分条件的顶点,通过进一步提取地形的特征采用Loop算法细分局部区域。最终对满足一定条件的边界顶点进行适当的几何优化以使仿真结果更加逼真。算法在场景仿真结果上比原始算法更加细腻,并且在实时漫游过程中漫游帧频平均值52.0303帧/秒,明显高于原始算法平均帧频36.187帧/秒。满足了虚拟仿真系统在漫游过程中对实时性的要求。 对于经典的纹理调和映射算法,尽管保持了纹理映射的有效性但是算法复杂度高,不能满足仿真系统实时性。基于这个问题,提出了根据评估值自适应选取目标函数的约束纹理映射方法。结合模型的参数化平面,计算模型特征点三角化后每一个三角块内部顶点的评估值,根据与阈值比较后的结果自适应选择目标函数。对于不能直接应用两种目标函数的三角块进行迭代细分,计算下一级三角块的评估值。实验表明算法能够很好的保持纹理的有效性,具有很高的使用价值。 在图像末制导仿真系统中,通过改变输入参数调整导弹的飞行姿态,伴随着图像出现平移、梯度变化等现象,并可以实现在指定帧图像出现特定渲染效果的目的。同时基于VC++和OpenGL完成了场景的调度绘制,实现了导弹末制导阶段虚拟场景的实时、动态模拟。 为了实现基于虚拟场景的注入式仿真,搭建了以PC上位机、FPGA为核心的注入式仿真平台为主要设备的注入式仿真测试系统。通过上位机在产生虚拟场景的同时,利用旋转映射技术将虚拟仿真场景保存为BMP格式的二维图像,并经过PCIe总线发送到FPGA板卡,板卡将图像缓存到DDR3 SDRAM中,然后将缓存的虚拟仿真图像通过Cameralink接口输出到图像处理平台。实现了基于虚拟仿真图像的注入式仿真测试。
其他摘要The virtual simulation technology on missiles homing phase is to simulated the scene of the missile terminal guidance stage. The simulation system can be considerded a tracking System or a detection system, and it can simulate some specific simulation scenes for that never used to be combat simulation,like cities. In the field of virtual simulation, there are two important indicators to decide simulation results of the virtual scene.One is the generation rate of virtual image,the other is the simulation results of simulation scenes.We can meet both ruquests for a simulation system with a small amount of data, but with regard to a simulation system with a large amount of data,things can be handled by another way. The more realistic scenario, the slower the rendering speed. Thus, two factors should be weighed. The paper expands the research on these two indicators, and includes these sevels aspects. In order to simulate realistic terrain in the simulation system, we generate terrain model by reading the DEM elevation data. At different phases of Missiles flight, we use different terrain textures with different resolutions of real images. To avoid the phenomenon of visual jumps between adjacent resolution terrain , we use transition textures made by corresponding fusion strategy.  This method is a realistic simulation of missile gradual process. For satellite blind terrain, a simulation algorithm of adaptive realistic terrain generation method based on ROAM algorithm was introduced. The terrain generated by ROAM is to be a base grid. Then we computer the integrated parameter Y of the lower grids. By comparison with a given threshold value to the Y parameters, determine whether to split or not. Extract the sharp features of the vertex that satisfy the conditions and split these vertexes with Loop algorithm. It generates a video stream by rotation mapping algorithm in real-time roaming process and sends to the injection simulation system to the DVI. Experimental results show that: the average of roaming frame rate of proposed algorithm is 45.1303 and the peak frame rate close to 50. The frame rate is higher than the average frame rate of the original algorithm. The proposed algorithm satisfies the requirements of the injection simulation system and the average of roaming frame rate is 45. In order to improve the effectiveness of texture mapping, I propose a constraint texture mapping method based on the evaluation value to determine which object function to select. This algorithm computes evaluation value of internal vertices of every triangular block after the feature point’s triangulation in the parameter plane. For the triangle both the objective functions are not suitable, we conduct a triangulation iteratively and calculate the evaluation value of triangles next level. Experiments show that this algorithm is dropped an average more than 75% of the time than the classical algorithm.The model of this algorithm is loaded into the real-time rendering system with high frame frequency. Experiments show that the algorithm has good robustness; repeated experiments show that the proposed algorithm can maintain good texture validity. In our virtual simulation system, the missiles fly at different positions corresponding to different simulation scenarios.It can adjust the parameters of the missiles when the user change input data. Meanwhile, the virtual simulation scene changes like translation, rotation or scaling.In this way; we can control the virtual simulation scene at any time. For example, we can add some special rendering results in any frame images. We use VC++ and OPENGL finished the simulation of virtual scene. I realized the simulation of virtual scene about the missile terminal guidance stage. In order to achieve injection simulation on virtual image, I built a simulation platform for injection.The platform includes PC、and FPGA . PC used to generate the virtual scene, and in this process PC computer will save the virtual scene as BMP pictures by rotation mapping technology. Then, the virtual image will be sent to FPGA through PCIe. And then ,the visual image will be sent to the image processing platform of the missile. Experimental results show that the injection simulation test based on virtual images is successful.
语种中文
文献类型学位论文
条目标识符http://ir.ciomp.ac.cn/handle/181722/41482
专题中科院长春光机所知识产出
推荐引用方式
GB/T 7714
王莹. 图像末制导仿真技术的研究[D]. 中国科学院大学,2014.
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